It is often desired to display a three-dimensional object as an image in a two-dimensional space, such as on a display screen or on a printed piece of paper. This can be accomplished by first describing the three-dimensional object as a composition of basic geometric shapes called “primitives” that define the shape of the object. One common primitive that is frequently used in this regard is a triangle. For example, three-dimensional surface models are commonly represented by meshes or networks of triangles. In such applications, each triangle can be defined in terms of its three vertices, each of which can in turn be defined using a suitable coordinate system, such as with Cartesian coordinates x, y, z. Once the primitives are adequately defined, they can be projected to form a two-dimensional image that can be generated using a raster device, such as a computer display or printer, in a process called “rasterization”. The raster device displays or otherwise generates the image using an array of picture elements (“pixels”), which are the smallest units that the device can use to represent the primitives.